Association between environmental lead/cadmium co-exposure in drinking water and soil and type 2 diabetes mellitus/obesity in Southern China

Abstract

Lead (Pb) and cadmium (Cd) in environment can be directly absorbed by drinking water and soil. However, data on human Pb and Cd exposure by drinking water and soil and its long-term consequence for type 2 diabetes mellitus (T2DM) and obesity are lacking. Our study aims to explore the association of typical heavy metals co-exposure in drinking water and soil to the community residents with T2DM and obesity indices in two cities of southern China. A cross-sectional study enrolling total 1,274 participants was performed and the local water and soil samples were collected in two communities in southern China. The average daily dose (ADD) of heavy metals was calculated to assess the exposure. The obesity indices comprise body mass index (BMI), waist-to-hip ratio (WHR) and waist circumference (WC). Binary, multiple logistic and linear regressions were employed for assessing the associations of Pb and Cd exposure with T2DM and obesity. The results showed that there weren't any significant correlations between ADDs of Pb/Cd and T2DM in community residents (all Ps>0.05). Compared with those with 18.5 ≤ BMI <24, with 1 μg/kg bw/d ADD of Pb increase in exposure are associated with 49.2–56.1% lower likelihood of overweight. Besides, with ADDs of Pb exposure was increased by 1 μg/kg bw/d and WHR decreasing by 0.01–0.02, and WC decreasing by 2.22–4.67 cm. We speculate that Pb causes weight loss because it damages the absorption function of the gastrointestinal tract as an initial injury. 1μg/kg bw/d ADD of Cd increase is associated with 100.9% upper likelihood of low weight in Model 1. It suggests that Pb/Cd pollution in the local environment was serious and harmful to residents' health. Government should introduce relevant oversight and accountability systems to improve the prevention and management of lifestyle-related chronic diseases in the future.

Trends in urine lead and associated mortality in US adults: NHANES 1999–2018

“…Hence, it is important to construct a database of mortality-risk profiles for each racial or ethnic group. Regarding weight status, there is observational evidence that higher to lower lead concentrations were significantly associated with a lower likelihood of being overweight relative to normal weight ( 36 ). In other words, the detrimental impact of body lead in overweight or obese individuals was lower than that in underweight or normal-weight individuals, which may, at least in part, account for the significant association between urine lead and cancer-specific mortality in underweight or normal-weight adults.…”

Association of multi-metals with the risk of hypertension and the interaction with obesity: A cross-sectional study in China

“…One is that acute or chronic lead exposure does not destroy TC, but may reduce TC levels, which may be the reason why non obese individuals with high lead level have a higher risk of hypertension than obese individuals ( 55 , 56 ). The Other is that Pb exposure may damage the gastrointestinal function and lead to weight loss ( 57 ). In addition, Pb exposure can reduce the basal level of cortisol and possibly reduce the risk of obesity by destroying the hypothalamic-pituitary-adrenal axis ( 58 ), which is consistent with the negative interaction between lead and obesity found in this study.…”

Multimetal exposure: Challenges in diagnostics, prevention, and treatment

“…In one of the recent study, Zhong et al [ 61 ] found negative correlation between multimetal exposure and obesity, although they did not focused on the investigation of underlying molecular mechanisms. In other study, Qu et al [ 64 ] attempted to find out a link between Pb and Cd co‐exposure, and the obesity indicators such as BMI, waist‐to‐hip ratio, and waist circumference. The findings indicated that there was no significant association between obesity and individuals’ average daily dose of Pb and Cd.…”

“…The findings indicated that there was no significant association between obesity and individuals’ average daily dose of Pb and Cd. [ 64 ] The National Health and Nutrition Examination Survey conducted on US population during 2003–2014 suggested that obesity and its associated chronic conditions such as hypertension and type 2 diabetes are linked to cumulative exposure to the mixtures of heavy metals. [ 39 ]…”